syzbot

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BUG: KCSAN: data-race in mas_walk / mas_wmb_replace

write to 0xffff888103b31d00 of 8 bytes by task 23465 on cpu 1:
 mte_set_node_dead lib/maple_tree.c:299 [inline]
 mas_put_in_tree lib/maple_tree.c:1579 [inline]
 mas_topiary_replace lib/maple_tree.c:1823 [inline]
 mas_wmb_replace+0x234/0x1760 lib/maple_tree.c:2083
 mas_wr_store_entry+0x54ff/0x5ad0 lib/maple_tree.c:-1
 mas_store_prealloc+0x43e/0x690 lib/maple_tree.c:4936
 vma_iter_store_overwrite mm/vma.h:616 [inline]
 vma_iter_store_new mm/vma.h:623 [inline]
 vma_complete+0x3c7/0x850 mm/vma.c:359
 __split_vma+0x5db/0x640 mm/vma.c:569
 split_vma mm/vma.c:599 [inline]
 vma_modify+0xbee/0xca0 mm/vma.c:1699
 vma_modify_flags+0x182/0x210 mm/vma.c:1719
 mprotect_fixup+0x3a2/0x680 mm/mprotect.c:759
 do_mprotect_pkey+0x6ae/0x960 mm/mprotect.c:937
 __do_sys_mprotect mm/mprotect.c:958 [inline]
 __se_sys_mprotect mm/mprotect.c:955 [inline]
 __x64_sys_mprotect+0x48/0x60 mm/mprotect.c:955
 x64_sys_call+0x2768/0x3020 arch/x86/include/generated/asm/syscalls_64.h:11
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x12c/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888103b31d00 of 8 bytes by task 23466 on cpu 0:
 ma_dead_node lib/maple_tree.c:544 [inline]
 mte_dead_node lib/maple_tree.c:559 [inline]
 mas_start lib/maple_tree.c:1186 [inline]
 mas_state_walk lib/maple_tree.c:2945 [inline]
 mas_walk+0x176/0x370 lib/maple_tree.c:4366
 lock_vma_under_rcu+0xc9/0x210 mm/mmap_lock.c:304
 do_user_addr_fault+0x232/0x1050 arch/x86/mm/fault.c:1325
 handle_page_fault arch/x86/mm/fault.c:1474 [inline]
 exc_page_fault+0x62/0xa0 arch/x86/mm/fault.c:1527
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618

value changed: 0xffff888118290dc1 -> 0xffff888103b31d00

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 23466 Comm: syz.4.4369 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
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